The construction and use of medical catheters is well known in the art. Balloons or other expansion devices are sometimes incorporated with catheters for such purposes as dilating blood vessels or other hollow structures (lumens) within a body, for temporarily anchoring an instrument within the body so that a surgical procedure can be performed, for cryotherapy and for phototherapy. Catheters including one or more balloons have been used to securely position light-emitters within a lumen such as in the human gastrointestinal tract, typically targeting a specific treatment area on a wall of the lumen to destroy malignant tumor cells that have preferentially retained a photosensitizing drug, while avoiding the irradiation of adjacent normal tissue.
Expandable catheters such as balloon catheters known in the art are generally occlusive devices that when expanded either conform to the interior shape of a lumen (sometimes referred to as being distensible balloon catheters), or force the lumen to expand to accommodate the size and shape of the balloon (sometimes referred to as being non-distensible balloon catheters). These devices are useful for such procedures as angioplasty, where a significant outward radial force is needed to expand an occluded blood vessel, or for situations where the exact placement of a medical instrument within a lumen is critical and requires complete immobilization of the lumen, for example, when a directed dose of radiation must be delivered to a specific surface segment of the lumen without irradiating adjacent surfaces.
Medical procedures using devices that immobilize or distend a lumen can put a patient at risk by blocking fluid flow, by abrading tissue, or by applying damaging force to the lumen or connected structures. Such devices also may not optimally present the interior surface of the lumen for uniform access during a medical procedure. In addition, some lumens have highly asymmetric or irregular shapes that are at best awkwardly addressed by existing balloon catheters and associated methods of use.
Thus, a significant need exists for improved procedures using expandable catheters and for new catheters that overcome the shortcomings associated with present devices.